The present invention refers to cocks for controlling the heating system of a motor vehicle.
These cocks comprise generally a flat valve member controlled by a lever and adapted to be brought in various positions starting from a position in which it fully cuts off the communication between a pipe section upstream the cock and a pipe section downstream the cock until a position in which it leaves the communication between the two pipe sections completely free. The sealing between the valve member and its seat in the housing of the cock is generally assured by a spring urging the valve member against its seat with the interposition of the flange of a guide sleeve for the spring.
It is the object of the present invention to simplify the sealing system of the valve member.
It has been ascertained that the pressure exerted on the valve member by the liquid flowing in the upstream pipe is per se sufficient to keep the valve member biased against its seat. Under these conditions in order to assure sealing, it is sufficient that the seat of the valve member be provided with a sealing ring and the control lever of the valve member be secured to the valve member by means of a screw, which screw also serves as a secondary means for insuring sealing of the valve against the seat sealing ring.
More particularly the cock according to the invention is of the type with a substantially flat valve member controlled by a lever and is characterized in that under operating conditions said valve member is permanently biased by the pressure of the heating liquid againt a sealing ring provided in the seat of the valve member in the cock housing, and in that the control lever is connected to the pin of said valve member by means of an adjusting screw.